1. Field of the Invention
The present invention relates generally to a data transmission/reception apparatus and method in a multi-antenna system, and a system using the same. More particularly, the present invention relates to an apparatus and method for transmitting/receiving data by antenna grouping, and a system using the same.
2. Description of the Related Art
Conventionally, the wireless channel environment, unlike the wired channel environment, shows a lower reliability due to multipath interference, shadowing, propagation loss, time-varying noise, interference, etc. This is the typical cause of obstruction to an increase in a data transfer rate, or a data rate, in mobile communication. Therefore, to implement a high-speed wireless environment for providing high-rate services, there is an urgent need for a solution to the foregoing problem.
A Multi Input Multi Output (MIMO) multi-antenna system is a conventional technology that has been proposed for addressing the problem of lower reliability in a wireless channel environment. The proposed MIMO multi-antenna system has an advantage of being capable of increasing performance of the system without addition of power and spectrum.
Generally, the multi-antenna system supports a Single-User (SU) mode and a Multi-User (MU) mode. A multi-antenna system supporting the SU mode transmits data to the same user via multiple transmission antennas, and a multi-antenna system supporting the MU mode transmits data to multiple users via multiple transmission antennas. The multi-antenna system supporting the MU mode has been proposed to obtain improved performance compared to the multi-antenna system supporting the SU mode, while minimizing an increase in the number of antennas and an increase in complexity of the hardware structure. In addition, the MU mode lays emphasis on improvement of the system's transmission capacity using Spatial Division Multiple Access (SDMA) scheduling.
The multi-antenna system is classified into a closed-loop scheme that depends on feedback information for resource allocation, and a closed-loop that does not depend on feedback information. For the closed-loop scheme, the most important issue is to prepare a scheme for minimizing feedback information for efficient resource allocation. Particularly, in the MU mode, there has long been a need for a reduction in the amount of feedback information.
Meanwhile, due to the diversification of the wireless communication services, there is a probability that terminals having different characteristics will coexist in the same service area. Therefore, a base station should be able to support various communication schemes. For example, the base station should be able to selectively support not only the SU mode but also the MU mode. In addition, for signal detection, the base station should be able to support both a terminal using a linear detection technique and a terminal using a nonlinear detection technique.
Accordingly, there is a need for an improved apparatus and method for generating and transmitting feedback information in a multi-antenna system using grouped antennas, and a data transmission apparatus and method for transmitting a data stream of a user according to a transmission mode selected depending on the feedback information.